Antimicrobial acid-catalyzed coating compositions

ABSTRACT

The antimicrobial acid-catalyzed coating composition of the invention is an acid-catalyzed coating composition formulated with at least one antimicrobial agent to provide antimicrobial activity to the coating composition and an article coated therewith.

This application claims priority from U.S. Provisional PatentApplication No. 60/570,214, filed May 12, 2004.

BACKGROUND OF THE INVENTION

The present invention relates to acid-catalyzed coating compositionshaving an antimicrobial agent(s) (“antimicrobial acid-catalyzed coatingcompositions”), coatings formed from antimicrobial acid-catalyzedcoating compositions, and articles of manufacture having such coatings.

Acid-catalyzed coatings are known for their superior physicalproperties, such as moisture and stain resistance, adhesion and wearresistance. These properties are due to the crosslinking of the polymersby an acid catalyst.

Generally, acid-catalyzed coating compositions are simply polymerscrosslinked as a result of a reaction catalyzed by an acid. They usuallyhave four components:

1. a crosslinking resin or resins, in many cases an aminoplast (e.g.,urea-formaldehyde, melamine-formaldehyde, etc.);2. one or more backbone resins (e.g., alkyds, acrylics, polyurethanes,etc.), which contain functional groups that will react with thecrosslinking resin(s);3. one or more carriers (water and/or organic solvents, blends oforganic sovents with or without water) for transporting the resins tothe article to be finished; and4. one or more acid catalysts (e.g., para-toluene sulfonic acid (p-TSA),toluene sulfonic acid (TSA), phenyl acid phosphate, n-butyl acidphosphate, etc.).

SUMMARY OF THE INVENTION

It has been found that acid-catalyzed coating compositions havingantimicrobial properties can be formulated. These coating compositionsprovide finished coatings having antimicrobial properties whilemaintaining other desired coatings properties.

In accordance with the invention, an antimicrobial agent is added to anacid-catalyzed coating composition to provide a coating withantimicrobial properties.

DETAILED DESCRIPTION OF THE INVENTION

An antimicrobial acid-catalyzed coating composition can be formulated byadding an antimicrobial agent to an acid-catalyzed coating composition.The formulation and manufacture of acid-catalyzed coatings are knowngenerally in the art and are commercially available under product namessuch as REL-VIRON, REL-PRIME, REL-PLAZ, AQUA-PLAZ and REL-VETTE, allavailable from Akzo Nobel Coatings Inc., High Point, N.C. Acid-catalyzedcoating compositions can be solvent-borne or water-borne.

As discussed herein, acid-catalyzed coating compositions generally havefour components; one or more crosslinking resins, one or more backboneresins, one or more carriers, and one or more acid catalysts. Thepresent invention adds an antimicrobial agent to the formulation for anacid-catalyzed coating composition. These elements are described in moredetail below.

The crosslinking resin or resins is usually an aminoplast.Representative examples of the crosslinker include, but are not limitedto, one or more of the following resins: melamine formaldehyde, blend ofurea and melamine formaldehyde, urea formaldehyde, etc. The selection ofthe crosslinker can influence the coating's cure speed, chemical andwater resistance, and formaldehyde emission.

The backbone resin(s) operates to plasticize the crosslinker and providethe applied film with toughness and flexibility. In addition, thebackbone resin(s) also influences other film properties and is selectedbased on the desired properties. Some of these properties include: curespeed, sandability, surface hardness, water resistance, color or lightfastness, and inherent film color (colorless or water white versusslightly amber).

Representative examples of the backbone resin include, but are notlimited to the following resins, or combinations thereof: alkyds,acrylics, acrylic polyols (e.g., styrene acrylics, etc.), polyurethanes,cellulose esters/modified cellulose products, vinyl resins,nitrocellulose resins, etc. These resins have functional groups forreacting with the crosslinker. For example, the resins can be modifiedby any number/type of polymers (e.g., nitrocellulose, vinyl, celluloseacetate butyrate (CAB), etc.) to yield the desired functional group(s).

Two common alkyds are coconut oil alkyds and tall oil fatty acid (TOFA)alkyds. Also, alkyds can be obtained from soya oil, linseed oil, cornoil, castor oil, etc. and are usually chosen based on oil length.

Representative examples of modified cellulose products/cellulose estersinclude, among others, nitrocellulose, cellulose acetate butyrate (CAB),etc.

A variety of vinyls are used in acid-catalyzed coating compositions.They are generally selected for enhancing adhesion, flexibility andchemical resistance.

Although these backbone resins are most common to solvent borneacid-catalyzed coating compositions, most of them also exist in either adispersed, colloidal or water-reducible form (e.g., an emulsion), andcan therefore be used in water-borne systems as well.

The acid-catalyzed coating composition can include one or morecrosslinker in any combination with one or more backbone resins.Representative, non-limiting examples of which include:

Acrylic backbone resin and urea formaldehyde crosslinker;Coconut alkyd and cellulose ester backbone resins, and a blend of ureaand melamine formaldehyde crosslinker;A blend of alkyd, acrylic polyol, and nitrocellulose as the backboneresin, and a urea formaldehyde resin crosslinker;A blend of alkyd and vinyl resins as the backbone resins, with amelamine formaldehyde crosslinker;Styrene acrylic emulsion backbone resin and a urea formaldehyde resincrosslinker;A coconut alkyd, or castor oil combined with an acrylic polyol as thebackbone resins, with a melamine formaldehyde crosslinker;Short oil coconut or tall oil fatty acid alkyd backbone resin, and ablend of urea and Melamine formaldehyde crosslinker;Tall oil fatty acid alkyd backbone resin, and a blend of urea andmelamine formaldehyde crosslinker; etc.

In any coating, the role of the carrier is to deliver the coating to thesubstrate. The carrier also performs some more specific roles in bothsolvent-borne and water-borne coatings. For solvent-borne coatings, thisinvolves solubilizing the binders and aiding in the flow and leveling ofthe delivered coating. Typical solvent-borne carriers include a varietyof organic solvents such as alcohols, aliphatic and aromatichydrocarbons, esters, ketones, etc. In water-borne coatings, the maincarrier is water. Other carriers common to water-borne coatings arecoalescing solvents, which help join the discrete acrylic particles intoa uniform film, and alcohols.

The type and amount of catalyst can be selected depending on whether thecoating is pre-catalyzed (one pack) or post-catalyzed (two pack).Representative examples of the catalyst include, but are not limited to,para-toluene sulfonic acid (p-TSA), phenyl acid phosphate (PAP), butylacid phosphate (BAP), etc. Of these, p-TSA is generally used forpost-catalyzed coatings, in an amount of 1-10%, 2-8%, by weight acidnon-volatile, while the others are usually used for pre-catalyzedcoatings, in an amount of 1-10%, 2-5%, by weight acid non-volatile.

A variety of antimicrobial agents are available in both organic andinorganic forms. Either type or mixtures of organic and inorganicantimicrobial agent(s) can be used in the acid-catalyzed coatingcomposition of the invention. Triclosan(2,4,4-trichloro-2-hydroxydiphenyl ether), sold by Ciba under the nameIrgaguard 81000, and Clariant's PDQ (N-(trichloromethylthio)phthalimide) are both organic antimicrobial agents. Inorganicantimicrobials are usually silver-based, such as AlphaSan from MillikenChemical and lrgaguard B5000 from Ciba. The antimicrobial agentfunctions to inhibit bacterial, fungal, microbial and other pathogen ornon-pathogen growth by controlling the growth of microorganisms oncontact with a surface coated by the composition of the presentinvention.

Other additives normally used in coatings, especially acid-catalyzedcoatings, and those used in antimicrobial compositions, can be includedas well. Representative examples of such additives include, but are notlimited to, wetting agents, defoaming agents, anti-sag agents, pigments,sheen controllers, plasticizers, (e.g., DINP (di-isonomylphthalate),etc.), stabilizers, alcohols (e.g., butanol, isobutanol, ethanol, etc.),silicone flow agents, other flow agents, polysiloxanes, polyethers,silica, polyethylene wax, polypropylene wax, etc.

Acid-catalyzed coatings may be applied by any method known in the art,including without limitation spraying, brushing, rolling, dipping, etc.They can be air dried and/or oven dried. For oven drying, dwell timesare often dependent on the configuration and operation of the finishingline. It is desirable to have longer dwell times (the length of time atthe recommended Board/substrate Surface Temperature (BST)) at higherBSTs. Usual cure conditions for an acid catalyzed coating are about 120°F.-about 150° F. BST, about 130° F.-about 140° F. BST, for about 1-about20 minutes, about 5-about 15 minutes. The average is about 130° F.(about 54° C.) BST for about 5 minutes. The maximum safe BST isdependent on the substrate.

Substrates to be coated with antimicrobial acid-catalyzed coatings alsovary widely including without limitation, wood, plastic, metal, etc. Itis desirable for many surfaces to have antimicrobial properties, variousfurnishings, cabinets, counters, floors, etc. Some non-limiting examplesof areas for such coatings are in the home, especially the kitchen andbathroom, the office, especially medical offices (desks, etc.),hospitals, etc., anywhere that is susceptible to bacterial/microbialcontamination.

Typical ranges of components in the antimicrobial acid-catalyzed coatingcomposition are listed below:Backbone resin: about 40-about 60% by weight of non-volatilesCrosslinker: about 20-about 40% by weight of non-volatilesCarrier: about 60-about 70% by weight of volatilesCatalyst: about 2-about 4% by weight of non-volatilesAntimicrobial agent: about 0.1-about 1% by weight of non-volatiles.The range of volatiles by weight in an acid-catalyzed coating is usuallyabout 40 to about 95%.Components and typical ranges of components in an acid-catalyzed coatingare listed below in % by weight of non-volatiles:Oils and Alkyd Resins about 5 to about 60%, about 10-about 50%, about20-about 40%Urea-formaldehyde Resins about 5 to about 60%, about 10-about 50%, about20-about 40%Melamine-formaldehyde Resins about 5 to about 60%, about 10-about 50%,about 20-about 40%Nitrocellulose Resin about 1 to about 40%, about 10-about 30%, about5-about 20%Vinyl Resin about 1 to about 40%, about 10-about 30%, about 5-about 20%Cellulose Acetate Butyrate about 1 to about 40%, about 10-about 30%,about 5-about 20%Para-Toluene Sulfonic Acid about 1 to about 10%, about 2-about 8%, about3-about 5%Toluene Sulfonic Acid about 1 to about 10%, about 2-about 8%, about3-about 5%Phenyl Acid Phosphate about 1 to about 10%, about 2-about 8%, about3-about 5%n-Butyl Acid Phosphate about 1 to about 10%, about 2-about 8%, about3-about 5%A list of solvents and typical ranges for their use in an acid-catalyzedcoating are identified in % by weight of volatiles:Methyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about20%Ethyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about20%Isopropyl about 1 to about 60%, about 5-about 50%, about 10-about 20%n-Propyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about20%Isobutyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about20%n-Butyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about20%Amyl Alcohol about 1 to about 60%, about 5-about 50%, about 10-about 20%Toluene about 1 to about 90%, about 10-about 80%, about 20-about 60%Xylene about 1 to about 90%, about 10-about 80%, about 20-about 60%1,2,4-Trimethylbenzene about 1 to about 90%, about 10-about 80%, about20-about 60%Acetone about 1 to about 90%, about 10-about 80%, about 20-about 60%n-Butyl Acetate about 1 to about 90%, about 10-about 80%, about 20-about60%Isobutyl Acetate about 1 to about 90%, about 10-about 80%, about20-about 60%n-Pentyl Proprionate about 1 to about 90%, about 10-about 80%, about20-about 60%.The range of volatiles by weight in an acid-catalyzed coating is about40 to about 95%.Typical ranges for the antimicrobial agent are identified in percentagesby weight of non-volatiles: about 0.01-about 10%, about 0.25-about 0.5%,about 1-about 5%, about 3-about 8%.

EXAMPLES Formulation Example 1

% Weight Xylene 31.400 Alkyd 21.100 Isobutyl Alcohol 19.200 Naphtha12.244 Urea-Formaldehyde Resin 8.800 Melamine-Formaldhyde Resin 5.263Para Toluene Sulfonic Acid 1.900 Antimicrobial Agent 0.093The antimicrobial agent has been calculated as 0.25% by weight ofnon-volatiles.

Formulation Example 2

% Weight Alkyd and acrylic polyol backbone 14.220 Urea-FormaldehydeResin 4.650 Carrier 72.392 Nitrocellulose 5.700 Phthalate plasticizer2.850 Catalyst 0.120 Antimicrobial Agent 0.068The antimicrobial agent has been calculated as 0.25% by weight ofnon-volatiles.

Formulation Example 3

% Weight Alkyd and acrylic polyol backbone 26.800 Melamine formaldehyderesin 6.700 Carrier 63.535 Nitrocellulose 0.880 Catalyst 2.000Antimicrobial Agent 0.085The antimicrobial agent has been calculated as 0.25% by weight ofnon-volatiles.

Examples 1-2 and Comparative Example 3

For Examples 1 and 2, two REL-VIRON topcoat formulations (available fromAkzo Nobel Coatings Inc.) were modified by the addition of Irgaguard B1000 (available from Ciba Specialty Chemicals), an antimicrobial agent.The Irgaguard B 1000 was mixed into the first REL-VIRON topcoat to aconcentration of 0.25% by weight of non-volatiles and into the second toa concentration of 0.5% by weight of non-volatiles. Two test panels ofmaple, cherry and walnut, which had been stained and sealed, weresprayed with the antimicrobial REL-VIRON topcoats to a thickness ofabout 3 wet mils. The coated panels were flash dried at ambienttemperature for 15 minutes, then oven dried for 15 minutes at 135degrees F., then cooled to ambient temperature. The finished panels wereallowed to age for approximately 2 weeks. The coated panels were testedfor typical coating properties. These tests and the results are reportedin Table 1 below.

For antimicrobial tests, the panels were placed in an approximately 2×2cm diameter sample of agar (casin-soy meal peptone) containing bacteriafrom a diluted overnight culture (0.85% NaCl solution pH 7.2+/−0.2 fordilution) of. Staphylocuccus areus ATTCC 9144 and a similar samplecontaining Escherichia coli NCTC 8196. The antimicrobial activity wasevaluated by both zone of inhibition and the Vinson Rating afterincubation at 37 degrees C. for 24 hours. Both evaluation methodsindicated good antimicrobial activity.

Comparative Example 3

A comparative test panel was prepared in the same manner as described inthe above Examples 1-2, except no antimicrobial agent was added to theREL-VIRON topcoat. The coated panel was tested for typical coatingproperties. These tests and the results are reported in Table 1 below.

The comparative test panel was also tested for antimicrobial activityaccording to the method described in the Examples. No antimicrobialactivity was indicated.

TABLE 1 Ex. 1 Ex. 2 Comp. Ex. 3 ASTM 0.25% 0.50% 0% PLASTICIZERMIGRATION HOT D-2199 No Change No Change No Change COLD D-2199 No ChangeNo Change No Change COLD CHECK TEST 10 CY D 1211 PASS PASS PASS DFT D6132 (ON WOOD) 2.4 MILS 2.3 MILS 2.2 MILS STAIN RESISTANCE TEST 10%CITRIC ACID D 1308, 3.1.1 10 10 10 WATER D 1308, 3.1.1 10 10 10 MUSTARDD 1308, 3.1.1 10 10 10 IODINE D 1308, 3.1.1 10 10 10 INK D 1308, 3.1.110 10 10 COFFEE D 1308, 3.1.1 10 10 10 AMMONIA D 1308, 3.1.1 10 10 8RUBBING ALCOHOL D 1308, 3.1.1 10 10 6 VINEGAR D 1308, 3.1.1 10 10 10NAPTHA D 1308, 3.1.1 10 10 10 ACETONE D 1308, 3.1.1 10 10 10 LIQUID JOYD 1308, 3.1.1 10 10 10 FINGERNAIL POLISH D 1308, 3.1.1 10 10 10MERTHIOLATE D 1308, 3.1.1 10 10 10 FADE RESISTANCE G-53 8 8 8 ADHESION(MAR BAR)* D-5178 (MODIFIED) PASS PASS PASS *Modification is the use ofthe Model 1001 Organic Coatings adhesion tester in place of the Belmar(Balanced Beam) tester. Ratings: 1 = Fail, 10 = No effect

Comparative Example 4 and Examples 5-8

In Comparative Example 4, a test panel was sprayed with REL-VIRON(available from Akzo Nobel Coatings Inc.). In Examples 5-8, thepercentages of antimicrobial agent are given by weight of non-volatiles.Example 5 is a test panel sprayed with REL-VIRON formulated with 0.25%Ciba's IRGAGUARD B1000. Example 6 is a test panel sprayed with REL-VIRONformulated with 0.5% Ciba's IRGAGUARD B1000. Example 7 is a test panelsprayed with REL-VIRON formulated with 0.25% Clariant's PDQ. Example 8is a test panel sprayed with REL-VIRON formulated with 0.5% Clariant'sPDQ.

The coating properties of Comparative Example 4 and Examples 5-8 weretested and the results are shown in Table 2.

TABLE 2 ASTM Reference Comp. Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 PhysicalTests Model 1001 Adhesion (Belmar) D 5178 (modified)* Pass Pass PassPass Pass Plasticizer Resistance (Hot) D 2199 No change No change Nochange No change No change Plasticizer Resistance (Cold) D 2199 Nochange No change No change No change No change Hot/Cold Check Test D1211 Pass Pass Pass Pass Pass Fade Resistance G-53 8 8 8 8 8 Dry FilmThickness D 6132, on wood 2.2 mils 2.4 mils 2.3 mils 1.8 mils 1.8 milsStain Resistance (Reagents) 10% Citric Acid D 1308, 3.1.1 10 10 10 10 10Water D 1308, 3.1.1 10 10 10 10 10 Mustard D 1308, 3.1.1 10 10 10 10 10Iodine D 1308, 3.1.1 10 10 10 10 10 Ink D 1308, 3.1.1 10 10 10 10 10Coffee D 1308, 3.1.1 10 10 10 10 10 Ammonia D 1308, 3.1.1 8 10 10 10 10Rubbing Alcohol D 1308, 3.1.1 6 10 10 10 10 Vinegar D 1308, 3.1.1 10 1010 10 10 Naptha D 1308, 3.1.1 10 10 10 10 10 Acetone D 1308, 3.1.1 10 1010 10 10 Liquid Joy Detergent D 1308, 3.1.1 10 10 10 10 10 Fingernailpolish D 1308, 3.1.1 10 10 10 10 10 Merthiolate D 1308, 3.1.1 10 10 1010 10 RATINGS: 1 = Fail, 10 = No effect *Modification is the use of theModel 1001 Organic Coatings adhesion tester in place of the Belmar(Balanced Beam) tester.

Comparative Example 9 and Examples 10-13

In Comparative Example 9, a test panel was sprayed with REL-VETTE(available from Akzo Nobel Coatings Inc.). In Examples 10-13 thepercentages of antimicrobial agent are given by weight of non-volatiles.Example 10 is a test panel sprayed with REL-VETTE formulated with 0.25%Ciba's IRGAGUARD B1000. Example 11 is a test panel sprayed withREL-VETTE formulated with 0.5% Ciba's IRGAGUARD B1000. Example 12 is atest panel sprayed with REL-VETTE formulated with 0.25% Clariant's PDQ.Example 13 is a test panel sprayed with REL-VETTE formulated with 0.5%Clariant's PDQ.

The coating properties of Comparative Example 9 and Examples 10-13 weretested and the results are shown in Table 3.

TABLE 3 ASTM Reference Comp. Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 PhysicalTests Model 1001 Adhesion (Belmar) D 5178 (modified)* Pass Pass PassPass Pass Plasticizer Resistance (Hot) D 2199 Faint imprint Faintimprint Faint imprint Faint imprint Faint imprint Plasticizer Resistance(Cold) D 2199 No change No change No change No change No change Hot/ColdCheck Test D 1211 Pass Pass Pass Pass Pass Fade Resistance G-53 6 8 8 88 Dry Film Thickness D 6132, on wood 1.8 mils 1.5 mils 1.3 mils 1.2 mils1.5 mils Stain Resistance (Reagents) 10% Citric Acid D 1308, 3.1.1 10 1010 10 10 Water D 1308, 3.1.1 10 10 10 10 10 Mustard D 1308, 3.1.1 10 1010 10 10 Iodine D 1308, 3.1.1 10 10 10 10 10 Ink D 1308, 3.1.1 10 8 1010 8 Coffee D 1308, 3.1.1 10 10 10 10 10 Ammonia D 1308, 3.1.1 10 6 8 610 Rubbing Alcohol D 1308, 3.1.1 8 10 8 10 8 Vinegar D 1308, 3.1.1 10 1010 10 10 Naptha D 1308, 3.1.1 10 10 10 10 10 Acetone D 1308, 3.1.1 6 4 66 6 Liquid Joy Detergent D 1308, 3.1.1 10 10 10 10 10 Fingernail polishD 1308, 3.1.1 10 10 10 10 10 Merthiolate D 1308, 3.1.1 10 10 10 10 10RATINGS: 1 = Fail, 10 = No effect *Modification is the use of the Model1001 Organic Coatings adhesion tester in place of the Belmar (BalancedBeam) tester.

Bacterial growth inhibition testing was conducted for ComparativeExamples 4 and 9, and Examples 5, 6, 10 and 11. Panels of each of theseExamples and Comparative Examples were placed on the top layer of theagar containing bacteria from diluted overnight cultures. Theantimicrobial activity as expressed by zone of inhibition (ZI) andVinson Rating (VR) was then examined after incubation at 37° for 24 h.In each case, the agar was a casein-soymeal peptone agar (CASO e.g. fromMerk Darmstad, Germany) for the bottom and top layer. The bacterialsuspension in each case was diluted in 0.85% NaCl solution pH 7.2+/−0.2.

The results of the bacterial growth inhibition testing are shown inTable 4. FIGS. 1-12 also show the results of bacterial growth inhibitiontesting, but the panels used for Comparative Examples 4 and 9 indicate azone of inhibition due to the panels of the examples and comparativeexamples being stored with their coatings face-to-face prior to testing.

TABLE 4 Staphylococcus aureus Escherichia coli ATCC 9144 NCTC 8196Samples: Wood ZI VR ZI VR Comp. Ex. 4 0/0 0/0 0/0 0/0 Ex. 5  9/10 4/43/4 4/4 Ex. 6 12/14 4/4 6/6 4/4 Comp. Ex. 9 0/0 0/0 0/0 0/0 Ex. 10 12/134/4 6/7 4/4 Ex. 11 18/20 4/4 10/12 4/4 All tests were performed twiceand both results are given in the table Legend: ZI = zone of inhibitionin mm VR = Vinson Rating, for growth under the disc 4 = no growth (goodactivity), 2 = isolated colonies (moderate activity), 0 = strong growth(no activity) (L. J. Vinson et al. J. Pharm. Sci. 50, 827-830, 1961)

The results demonstrate the effectiveness of the inventiveacid-catalyzed coating composition formulated with an antimicrobialagent. Comparative Examples 4 and 9, without the antimicrobial agent,have no zone of inhibition (ZI) surrounding the sample, and noinhibition of growth under the sample, as shown by the Vinson Rating(VR). Examples 5, 6, 10 and 11 have significant and visible zones ofinhibition (ZI) and good activity under the sample (VR). There are alsosignificant differences when comparing the antimicrobial formulations ofREL-VIRON to those of REL-VETTE. These acid catalyzed coatingcompositions differ in that REL-VETTE includes a plasticizer and willhave nitrocellulose in about 20-about 30% by weight non-volatiles. Thereusually is no plasticizer in REL-VIRON and only about 1-about 10% byweight non-volatiles of nitrocellulose.

1. A coating composition comprising an acid-catalyzed coatingcomposition comprising one or more aminoplast resins, one or morebackbone resins which contain functional groups that will react with theaminoplast resin or resins, at least one acid catalyst, and at least oneorganic antimicrobial agent.
 2. The coating composition of claim 1,wherein the antimicrobial agent comprises at least one a silver-basedantimicrobial agent.
 3. The coating composition of claim 1, wherein thecoating composition comprises: about 40-about 60% by weight ofnon-volatiles of said at least one backbone resin; about 20-about 40% byweight of non-volatiles of at least one crosslinker; about 60-about 70%by weight of volatiles of at least one carrier; about 2-about 4% byweight of non-volatiles of said at least one catalyst; and about0.01-about 1% by weight of non-volatiles of said at least oneantimicrobial agent.
 4. An antimicrobial acid-catalyzed coatingcomposition comprising at least one antimicrobial agent, a plasticizer,at least one acid catalyst and about 20-about 30% by weight ofnon-volatiles of nitrocellulose.
 5. An article coated with theantimicrobial acid-catalyzed coating composition of claim
 1. 6. Thecoating composition of claim 1, wherein the antimicrobial agentcomprises about 0.01%-about 0.5% by weight of non-volatiles.
 7. Thecoating composition of claim 4, wherein the coating compositioncomprises: about 40-about 60% by weight of non-volatiles of at least onebackbone resin; about 20-about 40% by weight of non-volatiles of atleast one crosslinker; about 60-about 70% by weight of volatiles of atleast one carrier; about 2-about 4% by weight of non-volatiles of the atleast one acid catalyst; and about 0.01-about 1% by weight ofnon-volatiles of the at least one antimicrobial agent.
 8. A coatingcomposition comprising an acid-catalyzed coating composition comprisingone or more aminoplast resins, one or more backbone resins which containfunctional groups that will react with the aminoplast resin or resins,at least one acid catalyst, and at least one organic antimicrobialagent, wherein the acid catalyst is para-toluene sulfonic acid, phenylacid phosphate or butyl acid phosphate.
 9. The coating composition ofclaim 8, wherein the coating composition comprises: about 40-about 60%by weight of non-volatiles of the one or more backbone resins; about20-about 40% by weight of non-volatiles of at least one crosslinker;about 60-about 70% by weight of volatiles of at least one carrier; about2-about 4% by weight of non-volatiles of the at least one acid catalyst;and about 0.01-about 1% by weight of non-volatiles of the at least oneantimicrobial agent.
 10. The coating composition of claim 1, wherein theantimicrobial agent comprises about 0.25%-about 0.5% by weight ofnon-volatiles.
 11. The coating composition of claim 4, wherein theantimicrobial agent comprises about 0.01%-about 0.5% by weight ofnon-volatiles.
 12. The coating composition of claim 8, wherein theantimicrobial agent comprises about 0.01%-about 0.5% by weight ofnon-volatiles.